Okay okay i will preface with all of my hcs for charles are based off my theory in my pinned but

Little astolfo clearly needs a paladin to teach him so vanitas did aswell and who better than charles

Charles has been shown in his brief screentime to be cruel to astolfo and i dont think this would be anything new to him. Hes met a kid like that before he knows how to get to them (little vani)

Even before vani i think charles would have still had a lot of experience and i take him as someone who would absolutely mess with his prey mentally and physically before killing them

SO how does this translate to vani/charles

Im gonna be greedy needy and horny about all of it tbh

The crux of this is that Charles is Vanis first love

Vani also learned from SOMEWHERE everything he did with Jeanne

Who better to teach him to manipulate vampires with sexual acts than my fucked up little princess (charles)

He would have done the same to little vani

He kind od always needs a person to latch onto (his dad-misha-luna-dante-noe) and charles would have noticed

Hes a sleepy kind og guy its not a stretch to say hed consider a bed a reward-snuggles and cuddles-sex even

Of course charles isnt kind i mean hes groomy vani at this point but vani also would have had interests and ideas from his time in the traveling show that he can not keep so we get to the source of his scars

I like to picture charles as a whip kind of guy but it wouldnt be a stretch to say he used joyeuse against him when he was acting up tho his scars could also be argued as scratches from luna BUT IM GREEDY AND NEEDY

This may be born from my desire for vani to absolutely be sexually assaulted in his childhood and churchfolk often being found to do the same thing

Or it could be charles pretty and i want him to have vani history who knows my penis sure doesnt